Electric motor



BEST AVAiLABLE CGPa Aug. 3 192s 1,594,398

J. WOLKOFF ELECTRIC MOTOR Fil ed Jan. 20, 1923 ashets-sheei 1 i if INVENTOR A TTORNE Y8 BESTAVAFLAB LE COPE J. WOLKOF ELECTRIC 'MoToR Filed Jan.

ATTORNEYS 32$? wmm w so? 1' Aug. 3 1926. 1,594,398

J. WOLKOFF ELECTRI C MOTOR Filed Jan. 20 1923 ssheets-sneot s X t INVENTORZY 115 JOhILMJZ/[Off' ATTORNEYS Patented Aug. 3, 1926. AILABIE UNITED STATES JOHN WOLKOFF, OF EAST ORANGE, NEW JERSEY.

ELECTRIC moron.

Application filed January 20, 1928. Serial 814,017.

An-object of this invention is to provide means whereby the direction of rotation of the armature may be reversed by varying the positions of the commutator brushes with respect to the poles of the field magnets.

Another object of the invention is to provide a simple and improved yieldable holder for the commutator brushes, said holder being rotatively adjustable forthe purpose of reversing the rotation of the commutator; varying the speed of the armature and bring ing said armature to a stop. This latter result is obtained by placing the brushes in a neutral or centra position with respect to the field magnets and the magnetic lines of force flowin between said magnets.

Another 0 ject of the invention is to provide a simple means-for reducing the speed of the motor by cutting out two of the brushes and their contact bars.

There are other important objects and advantages of the invention which will appear hereinafter, and which will-be. apparent to one skilled in the art. U

In the drawings, Figure 1 is a vertical longitudinal sectional view' through the mo- Fig. 2 a detail vertical sectional view of a portion of the brush holder;

Fig. 3 a perspective view of the brush holder detached; v

Fig. 4 a vertical sectional view substantially on the line 4-4 of Fig. 1, portions of the inner frame being broken away to more clearly showthe construction;

Fig. 5 an elevation of the inner face of the brush holder showing the contact bars "on which the brush holders slide and with which they make electrical contact;

Fig. 6 a detail cross sectional view of a portion of the device for cutting out two of the commutator brushes;

Fig. 7 a detail elevation of the rotary bridge bar for cutting in and cutting out two of the brushes;

Fi 8 a' diagrammatic view of the motor and its connections;and.,.

Fig. 9 a view similar to Fig. 8 showing two of the brushescut out.

Referrin to the various parts by numerals. 1 esignates the supporting frame formed of cast iron and provided with a supporting base 2. This frame is formed with two large pole pieces 3, arranged at diametrically opposite points and extending inwardly in the same direction. Secured centrally to the supporting frame 1 and extending centrally into the armature chamber is an annular core 5, said core being permanently and rigidly connected to the frame 1 by screw bolts 6. Around the core 5 is arranged a large coil 7, said coil being con nected to the line or source of supply and to a contact bar, as will be fully hereinafter described. Secured centrally to the supporting frame and to the'inner end of the core 5 are bearings 8 for the armature shaft 9. The

outer end of the armature shaft is provided,

with a belt wheel 10 and the inner end thereof carries the us'ual commuta-tor bars 11. Rigidly keyed to the armature shaft is an annular frame 12 whiclnby means of bolts 13, support the armature 14. The armature is of the ordinary ring type, series wound. The coils 16 of the armature are connected to the commutator bars through the radiating rods 15, as clearly shown in Figs. 1 and 4. Asshown clearly in- Figs. 1 and 4 the armature is arranged to rotate around the central coil 7, and within the field poles 3. The

commutator bars are insulated from each other in the usual way and the entire commutator structure is n idly connected to the The commutator frame 12 by bolts 1 structure is insulated from the armature shaft and from the frame 12 by any suitable means; The field poles 3 are located outside of the armature ring while a sec- 3 0nd pair of field poles 3 are located within the ring. The poles 3 are located between the poles 3 and are carried by a bridge piece 4 which extends across the opposite face of the coil 7 from the frame 1 which supports the poles3.

The frame 12 and-the entire inner side of the supporting frame 1 is enclosed within a frame or casing'18. Mounted in the vertical side wall of the casing 18, and axially in line with the inner end of the armature shaft is a tubular stub shaft 19, a portion.

of said shaft extending within the casing and a portion thereof extending outside of the casing. On the exterior portion of the said stub shaft'is rigidly secured a knob or finger piece 20 by means of which the stub shaft may be rotated in either direction. The inner end of the armature shaft extends into the stub shaft 19 whereby said stub shaft will serve as a bearing for one end'of the armature shaft. Rigidly secured to the inner end of the stub shaft, close to the inner side of the casing 18, is a plate 21.

1 or lea radially arranged brush holder 24. Thesebrush'holders are rectangular and tubular and mounted in each oneis a brush block 25. The brush holders are radially arranged directly on the commutator bars.

and the inner-faces of the brush blocks bear There are four of these brushes '25 and they are diametricallyg opposite points, as clearly arranged to engage thecommutator bars at shown in Fig. 4.- Eachbrush block is yield- -ingly'forced inwardly to engage the commutato'r by a spring 26, one end of said spring bein connected to the outer end o the 'brus and the other end of said spring being connected to the brush holder. Itis manifest that by rotating the finger piece or knob ,20

in either direction the brusheswillbe rotatively adjusted around the commutator.

Withinfthe casing 18 is mounted a ring 27 ofinsulating material theinner-face ofsaid ring bein of'the brush v sulating ring '27 are four segmental contact adjacent to theouter sides bars. 28+,'-2 8+ 'and 28- 28-. Each contact bar is arranged-to be engaged, and in electrical contact with the outer portion of abr'ush holder. The spring 22' yieldin'gly holds the brush 'holders in engagement with the-contact'bars, as clearly-shown in Figs. 1 and 2. To prevent the'brush holders from being moved to their respective contact bars the plate 21 is provided with a stop pin 29 which enters and travels in a -'seginental slot 30 formed in the rigid casing 18, said slotted pin limiting the oscillation or rotation of the plate 21 and the brush:

holders.- The slot 30 is of sufficient length to permit the brushtholdersato be" moved from one end of the contact bars to the other end thereof,-biit will prevent the brush holders being moved ofi theirv roper bars and into engagement with the a'jacentcontact bar in either. direction.

The contact bars- 28 are concentrically arranged and are spaced to coincide, with the I radial Y arrangement ofthe four. field poles.

This arrangement '-is -dia lustrated in Fig. 8. The rushholders are ammatically -il-.

similarly arranged, as shown in Fig. 4; and

'lia grammatically in Fig., 8. To the exterior of the enclosed casing 18, T and directly ,below the 1: uimutator and brush holders, is secured a l) ock 31, of insulating material. On this block are secured spring contact plates, d5" b ,c,'d,-'e and f.

These Contact plates areelectrically connected to the SOIIICGOf supply or line wires and to the four brush bars, as will be here-.

" Aime, one;

elders. Mounted'in the in-"" matter pointed out. Mounted in suitable bearings, and directly in front of the bar '31, -is a rotary cut out switch 32; This switch consistsof a horizontal shaft 33 carrying a c linder '34 of insulating material. Lmbedde in said cylinder are four bridge bars 35 and 35; 36 and 36. .The bridge bars 35 and 35' are short and are so placed in the cylinder 34 that they may be brought into engagement with the contact plates a andb, and d and e respectively; The bridge bars 36 and 36'jare longer than the bars 35 andare so arranged in the cylinder 34 that the bar 36 may be brought into engagement with the contacts a, b and c:and the bar 36 33 into engagementwith contact bars d,e and f. The cylinder 34 may be rotated by finger pieces 37 secured to the end of the shaft 33. The bridge bars are so arranged in the cyl- .inder' 34 that alljof the contacts a to f inelusive may bedisconnected from each other in order'to cut oif allcurr'ent from the motor and .thereb cured -to the "s aft- 33 is a hexagonal stop p1ater38 which is adapted to be engaged by -two* spring holding arms 39. diametricall arranged and adapted to engage diametri cally arranged faces on-the plate 38. By

this arrangement the cylinder 34 maybe readily stopped in threepositions; one of those positions "will bring the bridge bars 35 and 35 into'engagement with their contact'bars; another position will bring the bridge bars 36 aridfifi into engagement with their contact bars; and the ,third position will bring the plain surface of the insulatingcylinder 34"into engagement with the contact bars and thereby cut all current from the motor.-

In Figure 8 the motor is represented dia grammatically. The side of the line is render it inoperative." Se

connected directly to the'fi'eldcoil 7 and from there is led by connection 40 to conj tact a. As shown in this figure the bridge bars 36 and 36'-are in engagement with" the contact bars. The field coil contact a is connectedthrough bridge 36 to the contact bars I) and '0 and these bars are electrically connected by wires/1L. and 42"to the-"two brush contact bars 28+,gwlrih are complementary to the upperand lower field poles. The

side of the line is connected to contact bard and-this contact bar is connected through thebridge bar 36 to the contact bars e and 7. "These; latter bars are electri: cally connected by wires 43 and 44 to the two hriish bars 2 8-. arranged on the right an l'eft hand sides of the brush bars 28+ and are complementary with the field poles. As illustrated in Fig.8 the brushes are arranged centrally or midway between the "ends pf their con- The e brush bars are tact bars and are consequently centrailylocated with respect to the field poles. This is the neutral position of the brushes and the result ofthis neutral position is that the pull on the armature tending to rotate it is equal in opposite directions and the armature will not rotate. By rotating the brush holders clock-wise the balanced condition of the armature will be upset and the pull tending to rotate the armature clock-wise will dominate and the armature will be turned in varying the distance of the brush holders from the middle or neutral position to either end of the contact bar.

If it be desired to reduce the speed and the power of the motor theswitch 32 is rotated to bring the bridge bars 35 and 35 into engagement with the contact bars a and b, and d and e,, as illustrated in Fig. 9 of the drawings. This cuts out one brush contact bar 28+ and one contact bar 28--.' This willreduce the speed of the armature and likewise reduce the power thereof.

The form of motor shown in the drawings and described herein, but not claimed, will be claimed in a divisional application.

What I claim is: I 1. An electric motor comprising field poles, an armature shaft, an armature supbrushes and to the brush i 1-, eni Aiming 8 ported on said shaft, 8. commutator on the armature shaft, brush holders, a brush mounted in each holder and adapted to enage the armature, a segmental contact bar or each brush holder, each contact bar being arranged complementary to a field pole piece, means on rotatively mounting the rush holders to permit them to be simultaneously adjusted along the contact bars whereby the relation of each brush holder to its complementary pole piece may be varied, and means for yieldingly supporting the brush holders on their rotating means, said yieldin supporting means; pressing the brush olders against the contact'bars. I 2. An electric motor comprising field poles, an armature shaft, an armature supported on said shaft, a commutator on the armature shaft, brush holders, a brush mounted in each holder and adapted toengagevthe armatuie, a fixed segmental contact bar for each brush holder, a rotatable plate c ncentric with the armature shaft, radially arranged s ring arms carried by said plate, said radia arms carrying the brush holders on their outer ends and yieldingly ressing said holders against the contact ars, and spring means connected to the holders to yieldingly press the-brushes against the commutator. In testimony whereof I hereunto aflix my signature.

JOHN WOLKOFF. 

